GRADE guidelines: 9. Rating up the quality of evidence.

[1]  R. Beyth,et al.  Hemorrhagic complications of anticoagulant and thrombolytic treatment: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). , 2008, Chest.

[2]  D. Singer,et al.  Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). , 2008, Chest.

[3]  G. Lip,et al.  (8th Edition) Evidence-Based Clinical Practice Guidelines American College of Chest Physicians Antithrombotic Therapy in Atrial Fibrillation: , 2008 .

[4]  A D Oxman,et al.  Randomisation to protect against selection bias in healthcare trials. , 2011, The Cochrane database of systematic reviews.

[5]  Paul Glasziou,et al.  When are randomised trials unnecessary? Picking signal from noise , 2007, BMJ : British Medical Journal.

[6]  S. Weiner.  Contextualizing medical decisions to individualize care , 2004, Journal of General Internal Medicine.

[7]  P. McGettigan,et al.  Cardiovascular risk and inhibition of cyclooxygenase: a systematic review of the observational studies of selective and nonselective inhibitors of cyclooxygenase 2. , 2006, JAMA.

[8]  K. Wood,et al.  Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock* , 2006, Critical care medicine.

[9]  Ruth Gilbert,et al.  Infant sleeping position and the sudden infant death syndrome: systematic review of observational studies and historical review of recommendations from 1940 to 2002. , 2005, International journal of epidemiology.

[10]  Robert W Platt,et al.  Feeding effects on growth during infancy. , 2004, The Journal of pediatrics.

[11]  A. Charlett,et al.  Effectiveness of antibiotics in preventing meningococcal disease after a case: systematic review , 2004, BMJ : British Medical Journal.

[12]  S. Weiner.  Contextualizing medical decisions to individualize care: lessons from the qualitative sciences. , 2004, Journal of general internal medicine.

[13]  F. Song,et al.  Evaluating non-randomised intervention studies. , 2003, Health technology assessment.

[14]  S. Connolly,et al.  Pacemaker therapy for prevention of syncope in patients with recurrent severe vasovagal syncope: Second Vasovagal Pacemaker Study (VPS II): a randomized trial. , 2003, JAMA.

[15]  N. Andrews,et al.  Recall bias, MMR, and autism , 2002, Archives of disease in childhood.

[16]  G. Guyatt,et al.  A systematic review and meta-analysis of studies comparing mortality rates of private for-profit and private not-for-profit hospitals. , 2002, CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne.

[17]  H. Bedford,et al.  MMR vaccine—worries are not justified , 2001, Archives of disease in childhood.

[18]  M. Santini,et al.  Permanent Cardiac Pacing Versus Medical Treatment for the Prevention of Recurrent Vasovagal Syncope: A Multicenter, Randomized, Controlled Trial , 2001, Circulation.

[19]  M. Brignole,et al.  Dual-chamber pacing in the treatment of neurally mediated tilt-positive cardioinhibitory syncope : pacemaker versus no therapy: a multicenter randomized study. The Vasovagal Syncope International Study (VASIS) Investigators. , 2000, Circulation.

[20]  Jun Li,et al.  Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association , 1999, The Lancet.

[21]  S. Connolly,et al.  The North American Vasovagal Pacemaker Study (VPS). A randomized trial of permanent cardiac pacing for the prevention of vasovagal syncope. , 1999, Journal of the American College of Cardiology.

[22]  A. Sabrá,et al.  Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children , 1998, The Lancet.

[23]  J. Chmiel,et al.  Sexual Adventurism, High‐Risk Behavior, and Human Immunodeficiency Virus‐1 Seroconversion Among the Chicago MACS‐CCS Cohort, 1984 to 1992: A Case‐Control Study , 1996, Sexually transmitted diseases.

[24]  F Clerc,et al.  Long-term results of valve replacement with the St. Jude Medical prosthesis. , 1995, The Journal of thoracic and cardiovascular surgery.

[25]  F. R. Rosendaal,et al.  Thromboembolic and Bleeding Complications in Patients With Mechanical Heart Valve Prostheses , 1994, Circulation.

[26]  G. Friedman,et al.  A case-control study of screening sigmoidoscopy and mortality from colorectal cancer. , 1992, The New England journal of medicine.

[27]  J. Chmiel,et al.  Seroconversion, sexual activity, and condom use among 2915 HIV seronegative men followed for up to 2 years. , 1989, Journal of acquired immune deficiency syndromes.

[28]  M. Graffar.  [Modern epidemiology]. , 1971, Bruxelles medical.

[29]  I. Bross,et al.  Pertinency of an extraneous variable. , 1967, Journal of chronic diseases.

[30]  A. B. Hill.  The Environment and Disease: Association or Causation? , 1965, Proceedings of the Royal Society of Medicine.